Mixed-layer water oscillations in tropical Pacific for ENSO cycle

The main modes of interannal variabilities of thermocline and sea surface wind stress in the tropical Pacific and their interactions are investigated, which show the following results. (1) The thermocline anomalies in the tropical Pacific have a zonal dipole pattern with 160 W as its axis and a meridional seesaw pattern with 6-8 degrees N as its transverse axis. The meridional oscillation has a phase lag of about 90 to the zonal oscillation, both oscillations get together to form the El Nino/La Nina cycle, which behaves as a mixed layer water oscillates anticlockwise within the tropical Pacific basin between equator and 12 degrees N. (2) There are two main patterns of wind stress anomalies in the tropical Pacific, of which the first component caused by trade wind anomaly is characterized by the zonal wind stress anomalies and its corresponding divergences field in the equatorial Pacific, and the abnormal cross- equatorial flow wind stress and its corresponding divergence field, which has a sign opposite to that of the equatorial region, in the off-equator of the tropical North Pacific, and the second component represents the wind stress anomalies and corresponding divergences caused by the ITCZ anomaly. (3) The trade winds anomaly plays a decisive role in the strength and phase transition of the ENSO cycle, which results in the sea level tilting, provides an initial potential energy to the mixed layer water oscillation, and causes the opposite thermocline displacement between the west side and east side of the equator and also between the equator and 12 degrees N of the North Pacific basin, therefore determines the amplitude and route for ENSO cycle. The ITCZ anomaly has some effects on the phase transition. (4) The thermal anomaly of the tropical western Pacific causes the wind stress anomaly and extends eastward along the equator accompanied with the mixed layer water oscillation in the equatorial Pacific, which causes the trade winds anomaly and produces the anomalous wind stress and the corresponding divergence in favor to conduce the oscillation, which in turn intensifies the oscillation. The coupled system of ocean-atmosphere interactions and the inertia gravity of the mixed layer water oscillation provide together a phase-switching mechanism and interannual memory for the ENSO cycle. In conclusion, the ENSO cycle essentially is an inertial oscillation of the mixed layer water induced by both the trade winds anomaly and the coupled ocean-atmosphere interaction in the tropical Pacific basin between the equator and 12 degrees N. When the force produced by the coupled ocean-atmosphere interaction is larger than or equal to the resistance caused by the mixed layer water oscillation, the oscillation will be stronger or maintain as it is, while when the force is less than the resistance, the oscillation will be weaker, even break.

塑料压力管道热板焊接接头瞬时应力有限元分析

基于热粘弹性积分型本构关系,考虑材料性能依赖于温度变化及相变潜热的影响,利用有限元软件ANSYS热-力耦合及载荷步功能模拟结晶型高密度聚乙烯塑料压力管道热板焊接过程。并对焊接接头的应力分布进行有限元分析,得到了环向、轴向及径向瞬态应力分布规律。采用盲孔法和锯切法测量焊后残余应力,实测结果与数值分析基本吻合。

高密度聚乙烯塑料压力管道热板焊接头应力分布有限元分析

基于热粘弹性积分型本构关系,考虑材料性能依赖于温度变化及相变潜热的影响,利用AN SYS热-力耦合及载荷步功能模拟结晶型高密度聚乙烯(HDPE)塑料压力管道热板焊接过程,并对焊接接头的应力分布进行有限元分析,得到了环向、轴向以及径向瞬态应力分布的基本规律。采用盲孔法和锯切法测量焊后残余应力,实测结果与数值分析基本符合

孤岛油田中二北区Ng3～6储层建筑结构与油水分布规律研究

The reservoir of Zhongerbei region in Gudao Oilfield is a typical fluvial facies deposit, its serious heterogeneity of the reservoir caused the distribution of remaining oil in mature reservoirs is characterized by highly scattered in the whole field, and result to declination of production, tap potential and stabilize production is more difficult. Reservoir modeling based on lay scale can not fulfill requirement. How to further studied reservoir heterogeneity within the unit and establish the finer reservoir modeling is a valid approach to oil developing. The architectural structure elements analysis is the effectively method to study reservoir heterogeneity. Utilize this method, divide the reservoirs of Gudao Oilfield into ten hierarchies. The priority studying is sixth, seven hierarchies, ie single sand layers sand bodies By the identification of sixth, seven hierarchies, subdivide the reservoir to the single genetic unit. And to subdivide by many correlation means, such as isometry and phase transition, accomplish closure and correlation of 453 wells.Connectting fluvial deposit pattern, deposition characteristic with its log, build the inverting relation between “sedimentary facies” and “electrofacies” The process emphasize genetic communication and collocation structure of genetic body in space. By detailed architecture analyses sandbodies’ structure, this paper recognize seven structure elements, such as major channel, abandoned channel, natural levee, valley flat, crevasse splay, crevasse channel and floodplain fine grain.Combination identification of architectural structure elements with facieology and study of deposition characteristic, can further knowing genesis and development of abandoned channel. It boost the accuracy to separation in blanket channel bodies distribution, and provide reference to retrieving single channel boundary. Finally, establish fine plane and section construction. On basis architectural structure map, barrier beds and interbeds isopach map and mini-structure map, considering single thin layers to be construction unit, the main layer planimetric maps have drawn and the inner oil-water boundary have revealed. All account that architectural structure elements control remaining oil distribution in layer, and develop the study on architectural structure elements to direct horizontal well is succesful.

Calorimetric study of Wood alloy

The heat capacities of Wood alloy have been measured with an automatic adiabatic calorimeter over the temperature range of 80 similar to 360 K. The thermodynamic data of solid-liquid phase transition have been obtained from the heat capacity measurements. The melting temperature, enthalpy and entropy of fusion of the substance are 345.662 K, 18.47 J.g(-1) and 0.05343 J.g(-1).K-1, respectively. The necessary thermal data are provided for the low temperature thermodynamic study of the alloy.

Heat capacity and thermochemical study of trifluoroacetamide (C2H2F3NO)

The low-temperature heat capacities of trifluoroacetamide were precisely determined with a small sample precision automated adiabatic calorimeter over the temperature range from 78 to 404 K. A solid-to-solid phase transition, a fusion and a phase transition from a liquid crystalline phase to fully liquid phase have been observed at the temperatures of 336.911+/-0.102, 347.622+/-0.094 and 388.896+/-0.160 K, respectively. The molar enthalpies of these phase transitions as well as the chemical purity of the substance were determined to be 5.576+/-0.004, 11.496+/-0.007, 1.340+/-0.005 kJ mol(-1) and 99.30 mol%, respectively, on the basis of the heat capacity measurements. The molar entropies of the three phase transitions were calculated to be 16.550+/-0.012, 33.071+/-0.029 and 3.447+/-0.027 J mol(-1) K-1, respectively. Further researches of the thermochemical properties for this compound have been carried out by means of TG and DSC techniques. (C) 2000 Elsevier Science B.V. All rights reserved.

Heat capacity and thermodynamic properties of N-(2-cyanoethyl) aniline (C9H10N2)

The low temperature heat capacities of N-(2-cyanoethyl)aniline were measured with an automated adiabatic calorimeter over the temperature range from 83 to 353 K. The temperature corresponding to the maximum value of the apparent heat capacity in the fusion interval, molar enthalpy and entropy of fusion of this compound were determined to be 323.33 +/- 0.13 K, 19.4 +/- 0.1 kJ mol(-1) and 60.1 +/- 0.1 J K-1 mol(-1), respectively. Using the fractional melting technique, the purity of the sample was determined to be 99.0 mol% and the melting temperature for the tested sample and the absolutely pure compound were determined to be 323.50 and 323.99 K, respectively. A solid-to-solid phase transition occurred at 310.63 +/- 0.15 K. The molar enthalpy and molar entropy of the transition were determined to be 980 +/- 5 J mol(-1) and 3.16 +/- 0.02 J K-1 mol(-1), respectively. The thermodynamic functions of the compound [H-T - H-298.15] and [S-T - S-298.(15)] were calculated based on the heat capacity measurements in the temperature range of 83-353 K with an interval of 5 K. (c) 2004 Elsevier B.V. All rights reserved.

Highly ordered periodic mesoporous ethanesilica synthesized under neutral conditions

Highly ordered mesoporous ethanesilica (MES) with 2D hexagonal structure was synthesized from 1,2-bis(trimethoxysilyl) ethane under neutral conditions for the first time. Divalent salts, such as NiCl2, MgCl2, ZnCl2, ZnSO4 and Zn(NO3)(2), were used to help the formation of the ordered mesostructure. The MES samples were characterized by powder X-ray diffraction, nitrogen sorption, transmission electron microscopy, FT-IR, C-13 and Si-29 solid-state NMR and thermal gravimetric analysis. A phase transition from a disordered wormhole-like structure to an ordered P6mm structure was observed upon the addition of inorganic salts. The pore size of the MES decreases from 4.7 to 3.9 nm with increasing content of the inorganic salts. Fluoride was also found to be important for the formation of ordered MES under neutral conditions.

Measurements of the heat capacity of an azeotropic mixture of water and n-butanol from 78 to 320 K

Molar heat capacities of n-butanol and the azeotropic mixture in the binary system [water (x=0.716) plus n-butanol (x=0.284)] were measured with an adiabatic calorimeter in a temperature range from 78 to 320 K. The functions of the heat capacity with respect to thermodynamic temperature were established for the azeotropic mixture. A glass transition was observed at (111.9 +/- 1.1) K. The phase transitions took place at (179.26 +/- 0.77) and (269.69 +/- 0.14) K corresponding to the solid-liquid phase transitions of. n-butanol and water, respectively. The phase-transition enthalpy and entropy of water were calculated. A thermodynamic function of excess molar heat capacity with respect to temperature was established, which took account of physical mixing, destructions of self-association and cross-association for n-butanol and water, respectively. The thermodynamic functions and the excess thermodynamic ones of the binary systems relative to 298.15 K were derived based on the relationships of the thermodynamic functions and the function of the measured heat capacity and the calculated excess heat capacity with respect to temperature.

Thermodynamic properties of ethanol and gasoline blended fuel

The heat capacities (C-p) of five types of gasohol (50 wt % ethanol and 50 wt % unleaded gasoline 93(#) (E50), 60 wt % ethanol and 40 wt % unleaded gasoline 93(#) (E60), 70 wt % ethanol and 30 wt % unleaded gasoline 93(#) (E70), 80 wt % ethanol and 20 wt % unleaded gasoline 93(#) (E80), and 90 wt % ethanol and 10 wt % unleaded gasoline 93(#) (E90), where the "93" denotes the octane number) were measured by adiabatic calorimetry in the temperature range of 78-320 K. A glass transition was observed at 95.61, 96.14, 96.56, 96.84, and 97.08 K for samples from the E50, E60, E70, E80, and E90 systems, respectively. A liquid-solid phase transition and a solid-liquid phase transition were observed in the respective temperature ranges of 118-153 and 155-163 K for E50, 117-150 and 151-164 K for E60, 115-154 and 154-166 K for E70, 113-152 and 152-167 K for E80, and 112-151 and 1581-167 K for E90. The polynomial equations of Cp and the excess heat capacities (C-p(E)), with respect to the thermodynamic temperature, were established through least-squares fitting. Based on the thermodynamic relationship and the equations obtained, the thermodynamic functions and the excess thermodynamic functions of the five gasohol samples were derived.